You don't want the cold weather that comes with those winter months to sneak up on you and catch you off guard with regards to heating your home. Staying on top of having your furnace maintained ahead of time can stop you from being surprised on a cold day by a furnace that is giving you problems.
Also, when a furnace is about to fail, it can give off warning signs that gives you the opportunity to have someone come fix things and possibly save the furnace. If problems are ignored, they will often lead to compete furnace failure which means the need to completely replace it. Have your furnace maintained before winter rolls around, and make sure you catch the following red flags.
Issues with consistency
If you remember back to the previous winter when you have your furnace on you may be able to remember how the entire house would be warm and there wouldn't be issues getting it up to whatever temperature you set it on, or cold pockets that don't get heated up to par.
Now, if you are noticing your house isn't getting as warm as you are trying to get it, or there are areas of the home that aren't getting warm, then have things checked out because it likely needs furnace repair work.
Problems with odors
You may feel that it makes sense for your home to smell like something hot when the furnace is on, but this is actually false. While there may be an initial odor that comes from the registers when the furnace is first turned on due to dust in the system blowing out with hot air the first time the furnace is run, this should be the only time it happens.
If you continue to smell this odor coming from the registers when you are running the furnace, then you need to have someone come take a look and repair whatever is going on that is causing this to happen. You never want to continue running anything that suddenly has an odd smell to it, and this is the same for the furnace.
By calling a tech out when you discover issues going on with your furnace, you can relax in knowing you have done your part to expect a safer, more comfortable, and more efficient system that helps you to control the interior temp of your home.